The invention relates to methods for operating a cryostorage device which is arranged for storage and/or preservation of biological samples especially, and especially methods for data transmission during cryostorage as well as cryostorage devices for implementing such methods.
Cryostorage is a generally known technique for the storage and/or preservation of samples having a temperature-sensitive lifetime or stability, such as biological samples for example. Depending on the specific task, animal or vegetable products, organs of living beings or parts of biological systems, such as cells, cell constituents, macromolecules, micro-organisms, viruses or the like are transferred to a reduced-temperature state and stored. For preservation over long periods of time storage preferably takes place at liquid-nitrogen temperature or in a nitrogen-vapour atmosphere.
Patent Applications DE 100 60 889 and DE 101 44 925, which were unpublished at the foreign priority filing date of the present patent application, describe devices for the cryostorage of microscopically small biological samples. In these it is especially provided to deposit the samples in a cryostorage device each together with sample data which are characteristic to the relevant samples. There is a need to read or supplement the sample data in the data storages whilst the sample is in the cryopreserved state. Depending on the storage principle of the sample data, data-bus-bound or optical access to the data storage device has conventionally been realised. This may have the disadvantage that the handling capability of the cryostorage can be limited.
In data transmission technology transponder systems are increasingly replacing the conventional identification of objects using bar codes. Applications for example are known in automated production (automobile industry), monitoring technology (access control), in living animal identification or route tracking (e.g. courier services). Transponders having a wide range of designs matched to the particular application are known (for a review see K. Finkenzeller “RFID Handbook”, Hanser-Verlag, Munich, 2000).
The term transponder as an abbreviation of “transmitter” and “responder” designates a transmitting and receiving device which shows a reaction, e.g., gives an answer to a received and evaluated enquiry. In general, a transponder comprises a resonant circuit and an integrated circuit with a data storage device (e.g. EEPROM). Data transmission from the data storage (transponder storage) via a wireless transmission channel e.g. to a central control system takes place by using the resonant circuit as a transmitting or receiving antenna. The resonant circuit is tuned to a certain transmitting or receiving frequency (e.g. 62 kHz). For power supply especially during the write/read process the transponder is exposed to an electromagnetic alternating field at a different frequency, e.g., twice the frequency (e.g. 124 kHz) with which a current is induced in the resonant circuit. Transponders typically have a range of around 80 cm. The circuit typically contains a voltage regulator, a frequency divider and an encoder.
Advantages of transponders consist in their miniaturisability and access security. For example, space-saving transponders in foil form (so-called smart labels such as the “Tag-it” transponders from Texas Instruments) are known. Authentification and encryption methods are known for implementing access security. One problem with transponder systems however is that their transmission function is sensitively dependent on the ambient conditions. For example, metallic materials and strong electromagnetic foreign fields in the vicinity can limit the range of transponders to around 20 cm. For this reason, the use of transponder systems has so far been limited to the afore-mentioned tasks with sufficiently well controllable ambient conditions.
The object of the invention is to provide an improved method with which the above disadvantages of conventional cryostorage methods are overcome and which have a simplified handling capability and an extended range of application. Methods according to the invention should especially make it possible to achieve fast and secure access to sample data regardless of the operating state of a cryostorage device. The object of the invention is also to provide apparatus for implementing the method.
These objects are solved by methods and apparatus of the invention.